Symmetrical and unsymmetrical pyrazaboles

ABSTRACT

Described and claimed are the following: 1. Symmetrical pyrazaboles and sym-triazaboles of the formula   R, R1, R5 and R6 may be hydrogen, halogen, 1-pyrazolyl, alkyl, aryl, alkoxy, haloalkoxy, aryloxy, alkylamino, arylamino, azido, alkylmercapto and arylmercapto; X may be N or CR4; and R2, R3 and R4 may be hydrogen, alkyl, halogen, haloalkyl, aryl, cyano, alkoxy, arylamino, alkoxycarbonyl, nitro, acyl, mercapto and hydroxy with the proviso that R2 and R4 taken together may represent a fused benzo or naphtho structure. In the symmetrical pyrazaboles of this invention either R R1 R5 R6 or R R5 and R1 R6. 2. Unsymmetrical pyrazaboles and sym-triazaboles as represented by formula (I), wherein R and R1 may be hydrogen, halogen, 1-pyrazolyl, alkyl, aryl, alkoxy, haloalkoxy, aryloxy, alkylamino, arylamino, azido, alkylmercapto and arylmercapto; X may be N or CR4; R2, R3 and R4 may be hydrogen, alkyl, halogen, halo-alkyl, aryl, cyano, alkoxy, arylamino, alkoxycarbonyl, nitro, acyl, mercapto and hydroxy with the proviso that R2 and R4 taken together may represent a fused benzo or naphtho structure; and R5 and R6 are defined the same as R and R1 with the proviso that 1-pyrazolyl is excluded as a substituent in the case of R5 and R6. In the unsymmetrical pyrazaboles and sym-triazaboles of this invention, at least one of R and R1 is chemically distinguishable from R5 and R6. 3. The processes by which the pyrazaboles and sym-triazaboles of this invention may be prepared. 4. Polymers having incorporated therein the pyrazabole and symtriazabole structure. The compounds of this invention are useful as polymerization initiators, reducing agents and as reactants in the formation of condensation polymers containing the pyrazabole and symtriazabole moieties.

United @iates Patent Trofimenlro SYMMETRICAL AND UNSYMMETRICALPYRAZABOLES [72] Inventor: Swiatoslaw Trofimenko, Wilmington, Del.

[73] Assignee: E. I. du Pont de Nemours and Company, Wilmington, Del.

[22] Filed: Aug. 2, 1968 [21] Appl. No.: 749,623

Related US. Application Data [63] Continuation-in-part of Ser. No.429,113, Jan.

29, 1965, abandoned.

[52] US. Cl. ..260/310, 252/188, 260/308,

260/2 M, 102/31, 149/109 [51] Int. Cl. ..C07d 49/02 [58] Field of Search..260/310 [56] References Cited UNITED STATES PATENTS 3,261,844 12/ 1970Trofimenko ..260/299 Primary Examiner-Alex Mazel AssistantExaminer-Bernard Dentz AttorneyJames W. Ryan [57] ABSTRACT Described andclaimed are the following:

1. Symmetrical pyrazaboles and sym-triazaboles of the formula 51 Aug. 1,1972 2. Unsymmetrical pyrazaboles and sym-triazaboles as represented byformula (1), wherein R and R may be hydrogen, halogen, l-pyrazolyl, al-

kyl, aryl, alkoxy, haloalkoxy, aryloxy, alkylamino, arylamino, azido,alkylmercapto and arylmercapto; X may be N or CR; R R and R may behydrogen, alkyl, halogen,

halo-alkyl, aryl, cyano, alkoxy, arylamino, alkoxycarbonyl, nitro, acyl,mercapto and hydroxy with he proviso that R and R taken together mayrepresent a fused benzo or naphtho structure; and

R and R are defined the same as R and R with the proviso thatl-pyrazolyl is excluded as a sub stituent in the case of R and R in theunsymmetrical pyrazaboles and sym-triazaboles of this invention, atleast one of R and R is chemically distinguishable from R and R 3. Theprocesses by which the pyrazaboles and symtriazaboles of this inventionmay be prepared.

4. Polymers having incorporated therein the pyrazabole andsym-triazabole structure.

The compounds of this invention are useful as polymerization initiators,reducing agents and as reactants in the formation of condensationpolymers containing the pyrazabole and sym-triazabole moieties.

19 Claims, No Drawings CROSS-REFERENCE TO RELATED APPLICATION Thisapplication is a continuation-in-part of my copending application Ser.No. 429,113, filed Jan. 29, 1965, and now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to a new class of chemical compounds, the pyrazaboles andsym-triazaboles, which may be represented by the formula whereingenerally R, R, R and R may be hydrogen, halogen, 1- pyrazolyl, alkyl,aryl, alkoxy, haloalkoxy, aryloxy, alkylarnino, arylamino, azido,alkylmercapto and arylmercapto;

X may be N or CR; and

R ,R and R may be hydrogen, alkyl, halogen, haloalkyl, aryl, cyano,alkoxy, arylarnino, alkoxycarbonyl, nitro, acyl, mercapto and hydroxywith the proviso that R and R taken together may represent a fused benzoor naphtho structure. In the symmetrical compounds of this inventioneither R R R R or R R and R R. In the unsymmetrical pyrazaboles andsym-triazaboles of this invention at least one of R and R is chemicallydistinguishable from R and R There is the further proviso in the case ofthe unsymmetrical pyrazaboles and sym-triazaboles that neither R nor Rcan be l-pyrazolyl. Preferences for the aforementioned R groups whichhave been designated as halogen, alkyl, aryl and acyl are as follows:fluorine, chlorine, bromine and iodine, alkyl of up to 18 carbon atomsand especially lower alkyl of one to six carbon atoms, phenyl, phenylwith lower alkyl (of one to six carbon atoms) and/or halo (especiallychlorine, bromine or iodine) substituents, and carboxylic type acyl ofup to eight carbon atoms.

Additionally, this invention relates to the processes by which thecompounds of this invention may be prepared and to various polymers andcopolymers that may be produced therefrom.

2. Description of the Prior Art The following publications are ofinterest in connection with the present invention:

1. Trofimenko, J. Am. Chem. Soc., 88, 1842 (1966). This communicationdescribes some 4,8-symmetrically substituted pyrazaboles and generallydefines the area of boron-pyrazole chemistry.

2. Trofinienko, J. Am. Chem. $00., 89, 3165 (1967). This paper describesin detail the synthesis of 4,8-symmetrically substituted pyrazaboles andsym-triazaboles.

3. Trofimenko et al., J. Am. Chem. Soc, 89, 3148 and 3158 1967). Thesepapers describe physical studies on transition metal poly(l-pyrazolylborates).

4. Heitsch, Abstracts, l53rd Am. Chem. Soc. Meeting, L-l09 (April 1967).This Abstract entitled Synthesis of Fluoropyrazaboles by a Unique Routeto Boron-Fluorine Compounds describes inter alia the preparation of4-fluoropyrazabole and 4,4,8- trifluoropyrazabole by partialfluorination of pyrazabole.

So far as is known, there is not as yet any published literaturereference to the unsymmetrical pyrazaboles and sym-triazaboles of thisinvention.

SUMMARY OF THE INVENTION The discovery of a new class oforgano-inorganic acids formed from a compound containing an element ofGroup IIIA of the Periodic Chart of the Elements and an organicnitrogen-containing compound of the azole variety, for example,pyrazole, triazole or tetrazole, has been reported in US. Pat. No.3,261,844, issued July 19,1966,to Trofimenko. These highly ionizablecompounds are useful as sequestering agents and as corrosion inhibitors;moreover, these compounds chelate readily with the alkaline earth andtransition metals. Such compounds may be prepared by the reaction of acompound having the formula AR with a pyrazole, triazole or tetrazole.In the aforesaid AR A is an element of Group IIIA of the Periodic Chartof the Elements such as may be found in the Handbook of Chemistry andPhysics, 41st Edition, 1959) pgs. 448-9, and R is preferably halogen.

It has been discovered that by maintaining suitable control over thereaction temperature and the molar quantities of the reactants in thereaction of an azole and a compound of the formula AR as defined above,and more specifically, when the Group IIIA compound is a boronderivative, an entirely different and novel class of compounds may besynthesized, namely, the pyrazaboles and sym-triazaboles of thisinvention. Unlike the compounds disclosed in the aforesaid US. Pat. No.3,261,844, these new compounds are not highly ionizable and do not formsalts and chelates, but rather, are useful as polymerization initiators,reducing agents and especially as reactants in the formationcondensation polymers containing the pyrazabole and symtriazabolemoieties.

The symmetrical pyrazaboles and sym-triazaboles of this invention arerepresented by the formula not wherein the various R and X functionshave the previously stated significance. The distinctive feature of thesymmetrical compounds is that either R, R, R and R represent the samesubstituent or R R and R R The formation of these symmetrical compoundsmay be represented by the equation wherein X, R, R, R and R are asdefined previously and R is lower alkyl of one to six carbon atoms.Alternatively, the symmetrical compounds of the present invention may beprepared by the reaction of the pyrazole or triazole with a boronhalide, such as boron trichloride, instead of the arninoborane shown inthe equation.

As indicated, the products of the instant invention are formed using apyrazole or triazole as one of the reactants. In general, the azolecomponent can be any azole or substituted azole which has a hydrogenatom affixed to the l-nitrogen position. Examples of operable azoles areset forth in Table I.

TABLE I 3,4,5-Trimethylpyrazole 3-Ethylpyrazolc 3-EthynylpyrazoleB-Butadienylpyrazole 3-Methyl-5-phenylpyrazole 3-Bromo-4-phenylpyrazole4-Iodopyrazole 3,5-Dimethyl-4-nitropyrazole 3-Anilino-5-phenylpyrazole3-Methyl-4-hydroxy-5-phenyl- B-DimethylaminomethylindazoleBenzlflindazole (i.e., naphtho- [2,3-d1pyrazole) 3-Chloro-5-methyll,2,4-triazole 3-Benzoylpyrazole 3,5 -Diacetyl-4-phenylpyrazole3-Methylindazole (i.e., 3- methylbenzopyrazole) 3,5-Dichloroindazole3,5-Dimercaptol ,2,4-triazole 5,6-Diaminoindazole 5,6-Dihydroxyindazole5 ,7-Dimethylindazole 3-Hydroxy-5-phenyll ,2,4-

triazole The boron-containing compound which may be reacted with theazole may be one wherein only three substituents are attached to theboron. Alternatively, arninoboron compounds, for example, an aminoboranewherein the trisubstituted boron has been complexed with an amine, alsomay be employed. The borane component can be any member of a group ofcompounds broadly designated by the general formula QBRR'R" where Q issome electron pair donor such as an amine (preferably a tertiary amine)or an ether and R, R and R" may be selected from a group which consistsof hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, alkylamino,arylamino, l-pyrazolyl, azido, alkylmercapto and arylmercapto. A specialcase would encompass compounds wherein at least one of the R groups is ahydrogen atom, with the result that dimers containing B-ll-I-B bridging,e.g., diborane may be formed. In this case, Q may be considered asanother BRRR" unit. Finally, uncomplexed monomeric boranes BRR'R" may beused as well. Alternatively, the borane component may be defined as anysource of BRR'R". Such sources would include monomeric boranes,hydrogen-bonded borane dimers and borane complexes with diverse Lewisbases. Examples of operable borane reactants are set forth in Table II.

for example a boron trihalide, other than equimolar amounts of thereactants may be required. In this case the reaction is carried out withan approximately 3 to 1 ratio of azole to boron trihalide in order toinsure removal of all halogen. Examples 1 and 2, infra, exemplify thismethod of formation of the tetraazadibon'nes of this invention.

A unique feature of the compounds of this invention, one whichundoubtedly provides a stabilizing influence on the pyrazabole andsym-triazabole moieties, is that either adjacent nitrogen in the azoleportion of the structure (I) may act as the electron donor to the boron.Hence, although the structure (I) may be visualized as suggesting thatthere are two specific covalent and two specific dative N-B bonds, it isapparent that a modification of (I) which depicts the additionalresonance form of each azole ring reverses the covalent and dativebonds. Therefore, there is no distinction between the covalent anddative N-B bonds of the pyrazaboles and sym-triazaboles of thisinvention.

The unsymmetrical pyrazaboles and sym-triazaboles of this invention withdifferent substituents on the 4- and 8-borons may be synthesized by thefollowing route.

But-3-en- 1 -yloxydichloroborane a -Naphthyldichloroborane2-Methylallyloxydichloroborane PhenylbutoxybromoboraneDimethoxychloroborane Bis(2-chlorovinyl)chloroboraneDiethoxychloroborane Dibutylchloroborane DibutoxychloroboraneDibutylbromoborane Bis(2-chloroethoxy)chloroborane DimethylbromoboraneBis(3- chloropropoxy)chloroborane DiphenylchloroboraneBis(4-chlorobutoxy)chloroborane DiphenylbromoboraneDiallyloxychloroborane Ethylborane Bis(but-2-en-l-yloxy)chloroboraneMethylborane Bis( l-methylallyloxy)chloroborane DiethylboraneBis(2-methyla1lyloxy)chloroborane DimethylboraneBis(3-methylallyloxy)ch1oroborane Butylborane EthylenedioxychloroboranePhenylborane Diphenoxychloroborane Dimethoxyborane PhenoxydichloroboraneDimethylaminoborane Symmetrical products of this invention generally areobtained by heating approximately equimolar amounts of the azole andan'aminoborane falling within the formula QBRR'R" (defined supra) atelevated temperatures. This may be effected by carrying out the reactionin the melt or in a suitable inert solvent such as a hydrocarbon.Temperatures in the range of 25 to 150 C. are the preferabletemperatures. Although temperatures higher than 150 C. may be employed,they usually are avoided. When the reactants employed for the formationof the symmetrical products of this invention are an azole and acompound having the formula BRRR" (defined supra),

In the foregoing representation R, R, R R, R and X are as previouslydefined with the proviso in the case of the unsymmetrical pyrazabolesand sym-triazaboles that R and R cannot be l-pyrazolyl. M is a cationand Y is a leaving group. In the unsymmetrical products of this case atleast one of R and R is chemically distinguishable from R and R Withproper selection of the borane reactant, the process depicted above canlead not only to the unsymmetrical pyrazaboles and sym-triazaboles butto the symmetrical products as well. Generally, the process is carriedout in the following manner. A polypyrazolylborate anion (II) and aborane component where at least one substituent, Y, is capable of beingdisplaced as an anion are brought together, preferably in the presenceof an appropriate solvent or diluent. Good examples of Y are halogen,acyloxy or substituted acyloxy and alkylor arylsulfonate groups.Suitable solvents for the above reaction include the diverse ethers(e.g. tetrahydrofuran, 1,2-dimethoxyethane, anisole), aromatic andaliphatic hydrocarbons which would function as diluents and as solventsfor the product in the case of a heterogeneous reaction, and the simplehalocarbons, ketones or nitriles. The reaction can also be carried outin the absence of a solvent, if the borane component is a liquid, butsuch a procedure is generally less convenient.

The reaction is usually carried out at atmospheric pressure, there beingno need for higher pressures, although such may be employed if desired.Usually reaction proceeds exothermically upon mixing the reactants in asuitable solvent. At times the reaction must be moderated by cooling. Inthe case of heterogeneous reactions, especially when sizeable quantitiesof MY are precipitated, it is advantageous to reflux the reactionmixture while stirring it vigorously. The operable temperature range is40 to 200 C.; the preferred range being 20 to 120 C.

In the selection of a reaction temperature an accomodation must be madebetween a desirable reaction velocity and the stability of theparticular product formed.

In addition to the borate salts illustrated as reactants in theExamples, infra, many other poly l-pyrazolyl) borates are operable inthe process of this invention. Generally, these compounds are set forthin US. Pat. No. 3,261,844. A list, intended to be illustrative ratherthan exhaustive, of operable borates is given in Table III. Thesereactants may be employed in the form of isolated salts. Alternatively,they may be prepared in situ, proof of their presence resting on theirconversion to transition metal chelates.

TABLE III Tetramethylamrnonium hydro Sodium hydrotris l-pyratris-(l-pyrazolyl )borate zolyl )-borate Lithium hydrotris l-pyra- Cesiumhydrotris (l-pyrazolyl)-borate zolyl)-borate Tetramethylammoniumdihydro- Cesium tetrakis(1-pyrabis-( l-pyrazolyl)borate zoIyl)-borateSodium tetrakis( l-pyra- Lithium tetrakis( l-pyrazolyl)boratezolyl)-borate Tetramethylammonium tetra- Potassium hydrotris( l-symkis(l-pyrazolynborate triazolyl)borate Sodium diethylbis( l-pyra- Sodiumdibutylbis( l-pyra- The following compounds may serve as the boranecomponents: (a) all known and reported haloboranes, (b) acyloxyandsubstituted acyloxyboranes, (c) alkyland arylsulfonatoboranes, and (d)boronous anhydrides of the structure R BOBR where the departing anion isR The categories (b) and (c) need not be isolated but can be prepared insitu by reacting a trialkylborane or triarylborane with a carboxylic andsulfonic or sulfuric acid and these solutions can then be used directly.

A list of known boranes operable in the process of this invention isgiven in Table IV. These representative boranes were selected from M. F.Lapperts article, Organic Compounds of Boron, found at Chem. Revs, 56,959 (1956). The list is intended to be illustrative rather thanexhaustive.

Di-n-butoxychloroborane Di-n-octoxychloroborane Di-isobutoxychloroboraneDi-neopentoxychloroborane Bis( 2-chloroethoxy)chloroboraneDiphenoxychloroborane o-Phenylenedioxyboronous anhydrideDimethylboronous anhydride Diethylboronous anhydride Di-n-butylboronousanhydride Diallylboronous anhydride Diphenylboronous anhydrideDi-n-propylbromoborane Di-n-propyliodoborane Di-n-butylchloroboraneBischlorovinylchloroborane Di-n'butylbromoborane DiphenylfluoroboraneDiphenylchloroborane Diphenylbromoborane MethyldifluoroboraneMethyldichloroborane Methyldibromoborane EthyldifluoroboraneButyldibromoborane n-Pentyldifluoroborane s-Pentyldifluoroboranet-Pentyldifluoroborane n-l-lexyldifluoroborane CyclohexyldifluoroboranePhenyldifluoroborane p-Tolyldifluoroborane PhenyldibromoboranePhenyldichloroborane p-Tolyldichloroborane o-Tolyldichloroboranep-Methoxyphenyldichloroborane o-Methoxyphenyldichloroboranep-Ethoxyphenyldichloroborane -Naphthyldichloroboranep-Naphthyldichloroborane The following examples describe variousembodiments of this invention in greater detail. It is to be understoodthat these embodiments do not comprise the entire invention, but ratherare intended to be illustrative of a broader inventive concept for whichthe protection of the patent laws is being sought. The invention in itsbroader context finds supporting disclosure throughout the entirespecification, not in the examples alone. Examples 1-29 inclusivepertain to the symmetrical pyrazaboles and sym-triazaboles of thisinvention. Examples 30-39 inclusive pertain to the unsymmetricalpyrazaboles and sym-triazaboles of this invention.

EXAMPLE 1 4,4,8 ,8-Tetrakis( 1-pyrazolyl)Pyrazabole 6.8 Grams ofpyrazole were melted in a test tube and boron trichloride gas was passedinto the melt which was also heated externally with a Bunsen flame. Whenthe vigorous boiling stopped, the melt was cooled and yielded a watersoluble glass. One portion of the product was treated with a largeexcess of 50 percent aqueous sodium hydroxide, yielding a solid whichwas recrystallized from dimethylformamide. The same solid (confirmed byinfrared analysis) was obtained by subliming another portion of theglass at 300 C. at 1 mm. pressure. This product was identified as4,4,8,8- tetrakis( l-pyrazolyl)pyrazabole. Anal. Calcd. for

C H B N C, 50.9; H, 4.25; B, 5.09; Na, none Found: C, 51.4; H, 4.50; B,5.55; Na, none EXAMPLE 2 4,4,8,8-Tetrakis( l-pyrazolyl)Pyrazabole 68Grams 1 mole) of pyrazole were melted in a flask and boron trichloridewas passed into the flask just above the liquid surface. The solutionwas kept at 100 C. by periodic cooling. When the vigorous reactionceased, the flask was heated with a Bunsen burner. Vigorous boilingensued and an acidic vapor was evolved. When gas evolution stopped, theflask contents were distilled at aspirator vacuum. Fractions boiling atabout 150 C. and 150-180 C. were collected. They contained no boron (byflame test).

The pot residue was dissolved in water and treated with a large excessof 50 percent aqueous sodium hydroxide. The solid that precipitated wasfiltered, washed with water, and recrystallized from dimethylformarnideto yield 5.0 g. (7 percent) of 4,4,8,8- tetrakis(l-pyrazolyl)pyrazabole,m.p. 230-233 C., identical (by infrared analysis) with the product ofExample 1.

EXAMPLE 3 Pyrazabole Two moles of trimethylamine borane and two moles ofpyramle were refluxed with stirring in 400 ml. of toluene for 12 hours.Hydrogen and trimethylamine were evolved. The solution was stripped atreduced pressure yielding 146 g. (9l percent) of pyrazabole. [t waspurified by sublimation at reduced pressure; m.p. 81 C. Anal. Calcd. for

C l-l B Nn C, 45.2; H, 6.27; B, 13.5; MW. 160.

Found: C, 45.4; H, 6.09; B, 13.0; MW. 166. (by

vapor pressure lowering in chloroform at 37 C.

The infrared spectrum of the product has a characteristic BH multipletin the 2,2502,420 cm. region. The NMR spectrum (A60; CDCL,, TMSi)exhibits a doublet at 451 cps. and a triplet at 370 cps. with arearatios of 2:2: K] 2). The BH is exceedingly broad and can be seen onlyby integration; an area corresponding to four protons is centered around200 cps.

EXAMPLE4 4,4,8,8-Tetrakis( l-pyrazolyDPyrazabole The product of Example3 (34 g., 0.212 mole) was mixed with slightly over 0.424 mole ofpyrazole and heated with stirring until no more hydrogen was evolved.The melt was allowed to solidify and was then recrystallized from 500ml. of refluxing toluene. The solid was washed with ether and air-dried;m.p. 259-260 C.; yield 34 g. of 4,4,8,8-tetrakis( lpyrazolyl)pyrazabole.Anal. Calcd. for

C H B N C, 50.9; H, 4.25; MW. 424

Found: C, 51.8; H, 4.29; MW. 399 (by vapor pres sure lowering inchloroform at 37 C.

NMR (A60; CDCl TMSi): 454 cps. (doublet; area 4), 402 cps. (doublet;area 2), 495 cps. (triplet; area =1), and 363 cps. (triplet area=2).

EXAMPLE 5 pyrazabole was 31 g. (57 percent); m.p. C. Anal. Caled. for

C l-l B N C, 55.6; H, 8.33; MW. 216. Found: C, 56.6; H, 8.65; M.W. 210.(vapor pressure lowering in chloroform).

4 EXAMPLE6 2,6-Dibromopyrazabole 14.8 Grams of 4-bromopyrazole (0.1mole) and 7.3 g. of trimethylamine borane (0.1 mole) were refluxedovernight in 250 ml. of toluene. The solution was stripped, leaving asolid residue which was purified by sublimation. The purified analyticalsample of 2,6- dibromopyrazabole was recrystallized from xylene andresublimed; m.p. l44-145 C. Anal. Calcd. for

C H B Br N Br, 50.3; N, 17.6

Found: Br, 51.5; N, 17.7.

EXAMPLE 7 1 ,3 ,5 ,7-Tetraphenylpyrazabole 15.8 Grams (0.072 mole) of3,5-diphenylpyrazole were refluxed overnight with percent excesstrimethylamine borane in 350 ml. of a 1:2 xylenebenzene mixture.Trimethylamine was evolved. After stripping the reaction mixture theresidue was triturated with hexane and filtered. The solid wasrecrystallized from xylene. There were obtained 9.8 g. ofl,3,5,7-tetraphenylpyrazabole, melting at 203 C. with decomposition. Ananalytical sample was obtained by subliming at 250 C. and 1 mm.pressure. Anal. Calcd. for

C H B N C, 77.6; H, 5.70; N, 12.1

Found: C, 79.3; H, 5.69; N, 12.3.

EXAMPLE 8 4,4,8,8-Tetrachloropyrazabole 16.0 Grams (0.1 mole) of theproduct of Example 3 were dissolved in 800 ml. of carbon tetrachlorideand chlorine was bubbled in until the yellow color persisted. Hydrogenchloride was evolved and a white solid precipitated. The mixture wasstirred for an hour and filtered. There were obtained 29 g. (98 percent)of 4,4,8,8-tetrachloropyrazabole, melting at 2l5220 C. The product waspurified by recrystallization from chlorobenzene and by sublimation;m.p. 222223 C. Anal. Calcd. for

C H B Cl N C, 24.2; H, 2.01; C1, 47.7

Found: C, 24.9; H, 2.13; CI, 47.8.

EXAMPLE 9 4,4,8,8-Tetrabromopyrazabole l6 Grams (0.1 mole) of theproduct of Example 3 were stirred in 400 ml. of carbon tetrachloride atroom temperature. A solution of 64 g. (0.4 mole) of bromine in 100 ml.of carbon tetrachloride was added dropwise. Hydrogen bromide was evolvedexotherrnically. The hot solution was left stirring overnight and wasfiltered the next day to remove the precipitate. The product4,4,8,8-tetrabromopyrazabole was recrystallized from chlorobenzene;yield 25.0 g. (52 percent); m.p. 291-293 C. The material is sublirnablein vacuo. Anal. Calcd. for

Found: C, 16.2; H, 1.74; Br, 66.24.

EXAMPLE 10 sym-Triazabole heating leads to evolution of gas andpolymerization. Anal. Calcd. for

C H B N C, 29.7; H, 4.94; N, 51.8 Found: C, 31.2; H, 5.39; N, 51.8.

EXAMPLE l1 4,8-Diphenyl-4,8-bis( l-pyrazolyDPyrazabole Phenylborondichloride (28.6 g., 0.179 mole) was added to a suspension of 0.54 moleof pyrazolyl potassium in benzene and the mixture was refluxedovernight. The solid was filtered. It was stirred with water, filtered,and the insoluble part washed with water again. After drying 2.0 g. of4,8-diphenyl4,8-bis( lpyrazolyl)pyrazabole were recovered. The originalbenzene solution was stripped to dryness and the residue triturated withether. An additional 9.0 g. of product were obtained for a total yieldof 11.0 g. (28 percent). The compound was purified by recrystallizationfrom dimethylformamide and then by sublimation. It melts at 237240 C.Anal. Calcd. for

C H B N C, 64.9; H, 4.96; N, 25.2

Found: C, 64.8; H, 4.89; N, 24.9.

EXAMPLE l2 4,4,8,8-Tetraethylpyrazabole Sixteen Grams (0.1 mole) of theproduct of Example 3 were maintained for 3 hrs. at 250 C. in a bombunder 500 atm. ethylene pressure. A waxy solid weighing 5 1.5 g. wasobtained. It was distilled in vacuo to yield 7.4 g. of a fraction, b.p.68-110 C. at 1 mm. pressure and 10.5 g. of another fraction boiling at l10-148 C. at 1 mm. pressure. Both fractions solidified at roomtemperature. The first was a mixture of partially alkylated startingmaterial, as judged by the complex B-l-l stretching frequency in itsinfrared spectrum. The second was purified by recrystallization frompercent aqueous ethanol and identified as 4,4,8,8- tetraethylpyrazabole.

Anal. Calcd. for

C H B N C, 61.8; H, 9.56; B, 7.94

Found: C, 61.7; H, 9.35; B, 7.90.

The pot residue could not be distilled in vacuo. It contained 0.60percent boron, which corresponds to ethylene units per pyrazabole unit,indicating the copolymerizability of the pyrazaboles and symtriazaboleswith olefinic hydrocarbons.

EXAMPLE l3 Pyrazabole As A Reducing Agent Fifty moles of the product ofExample 3 and 0.1 mole of benzil were refluxed for 24 hours in 300 ml.of toluene. The solution was stripped at reduced pressure and theresidue triturated with ether. A white solid which separated wasfiltered and washed with ether; yield 7.0 g.; m.p. 234245 C. Thefiltrate was chromatographed on alumina yielding 2.4 g. 1 1 percent) ofunreacted benzil and 2.2 g. (11 percent) of meso 1,2- diphenylethyleneglycol, m.p. l34-136 C. (identified by comparing its infrared and NMR.spectra with those of an authentic sample, m.p. 136 C.).

The high melting solid was the reaction product of the pyrazabole and1,2-diphenylethylene glycol. This example demonstrates the usefulness ofthe products of this invention as reducing agents.

EXAMPLE l4 Polymer from Pyrazabole and Bis(p-aminophenyl)methane Inorder to demonstrate the usefulness of the compounds of this inventionin the formation of polymers, l millimoles of the product of Example 3and 20 millimoles of bis( p-arninophenyl)methane were mixed and melted.The mixture was heated with a hot-air gun. Hydrogen was evolved brisklyand the melt became viscous and finally solidified to a tough polymersubstantially comprised of a plurality of units having the structure:

EXAMPLE l5 Polymer from Pyrazabole and Hydroquinone Ten millimoles ofpyrazabole and mmoles of hydroquinone were mixed and melted. Uponheating to about 200 C. hydrogen was evolved and the melt solidified toa tough polymer substantially comprised of a plurality of units havingthe structure:

EXAMPLE 16 EXAWLE l7 Polymer from4,4,8,8-Tetrakis(1-pyrazolyl)pyrazabole and Hydroquinone Ten mmoles ofthe product of Example 1 and 120 mmoles of hydroquinone were mixed,melted and heated with an air gun. Pyrazole was evolved and the meltsolidified to a polymer similar to that from Examples l5 and 16.

EXAMPLE l8 Polymer from Pyrazabole and Pentaerythritol Five mmoles ofthe product of Example 3 and 5 moles of pentaerythn'tol were mixed,melted and heated with an air gun. The melt evolved hydrogen and thensolidified to a tough polymer substantially comprised of a plurality ofunits having the structure:

l mi The polymer softened, without melting, at 390 C. It could bepressed to a tough film of the type useful for packaging.

EXAMPLE 19 EXAMPLE 20 4,4,8,8-Tetraphenylpyrazabole A mixture of 22.6 g.(0.094 mole) of triphenylboron and g. (1 mole) of pyrazole was refluxeduntil benzene ceased to distill out (15 minutes); 8 ml. of benzene werecollected. The still-hot melt was poured into 800 ml. of water and leftstanding for several days. After filtration the crude product was washedwith water several times and was air-dried. It was purified byrecrystallization from 200 ml. of boiling toluene. There were obtained15.7 g. (72.4 percent) of crystalline 4,4,8,8-tetraphenylpyrazabole intwo crops. It is sublirnable and melts at 273-274 C. Anal. Calcd. for

C H B M: C, 77.6; H, 5.60; N, 12.0

Found: C, 77.9; H, 5.40; N, 11.6.

EXAMPLE 21 4,4,8,8-Tetrachloro-2,-dibutyl-1,3,5,7-tetra.methylpyrazabolePart A 3-Butylacetylacetone (33.2 g., 0.212 mole) was dissolved in 50m1. of methanol and added slowly to 11.0 g. (0.233 mole) of hydrazinehydrate in 100 ml. of methanol at C. The solution was stripped and theresidue was distilled to yield 25 g. (78 percent) of 4-butyl-3,5-dimethylpyrazo1e boiling at 119-120 C./ 1mm. lt solidified onstanding; m.p. 4445 C. Anal. Calcd. for

C H N C, 71.0; H, 10.6; N, 18.4

Found: C,71.1;H, 10.6; N, 18.5.

Part B A mixture of 0.1 mole of 4-butyl-3,5-dimethylpyrazole and 0.11mole of trimethylamine borane was refluxed overnight in 200 ml. ofbenzene. The solution was stripped to yield2,6-dibutyl-1,3,5,7-tetramethylpyrazabole in the form of an oil.

Part C The whole product from Part B was dissolved in 200 ml. of carbontetrachloride and exhaustively chlorinated by bubbling in chlorine untilthe yellow color persisted to yield 22 g. (94 percent) of crude4,4,8,8-tetrachloro-2,6-dibutyl- 1 ,3 ,5 ,7-tetrarnethy1- pyrazabole. Itwas purified by recrystallization from toluene and then by sublimation;m.p. 244245 C. Anal. Calcd. for

C H B CI N C, 46.4; H, 6.45; CI, 30.5

Found: C, 46.9; H, 6.65; Cl, 30.2.

EXAMPLE 22 1 ,3 ,5 ,7-Tetra1 is(trifluoromethyl)pyrazabole Part A 1 ,1,l,5,5,5-Hexafluoropentane-2,4-dione (208 g., 1.00 mole) was added at 5C. to a solution of 60 g. (1.2 moles) of hydrazine hydrate in 1.5 litersof ethanol. The solution was evaporated at aspirator vacuum and 40 C. toyield a white solid which was recrystallized from toluene. Two crops,148 and g., were obtained for a total yield of 72 percent of 3,5-bis(trifluoromethyl)-3,S-dihydroxypyrazolidine. The material waspurified by sublimation; m.p. 133135 C. Anal. Calcd. for

C H F N O C, 25.0; H, 2.50; F, 47.5

Found: C, 25.9; H, 2.73; F, 47.5

Part B 3 ,5-Bis(trifluoromethy1)-3 ,S-dihydroxypyrazolidine (173 g.,0.72 mole) was melted and heated with stirring. Water was distilled outslowly, then the temperature rose and material boiling at 147149 C./atm.came over and solidified. There were obtained 118 g. (81 percent) of3,5-bis-(trifluoromethyl)pyrazole; mp. 84 C. It had an unpleasantlypungent odor and sublimed with great ease. Anal. Calcd. for

C 11 F N C, 29.4; H, 0.98; F, 56.0; M.W. 204 Found: C, 29.5; H, 1.20; F,56.2; M.W. (cryoscopic in benzene), 208

Part C 3,5-Bis(trifluoromethyl)pyrazole (20.4 g., 0.1 mole) was stirredin 70 ml. of tetrahydrofuran and 100 ml. of a 1 molar solution of boranein tetrahydrofuran were added slowly. Hydrogen was evolved. The solventwas removed at aspirator vacuum and the residue was sublimed in vacuo toyield 20.1 g. (93.3 percent) of colorless crystals of1,3,5,7-tetrakis(trifluoromethyl)- pyrazabole. The material was purifiedfurther by 14 recrystallization from n-heptane and then by sublimation;m.p. 88-89 C. Presence of is attested by infrared bands at 2,600 and2,500 cmf.

EXAMPLE 23 4,4,8,8-Tetrach1oro-2,6-diisopropylpyrazabole PartA A mixtureof 4-isopropylpyrazole (5.1 g., 0.046 mole) and trimethylamine borane(3.38 g., 0.046 mole) was refluxed overnight in 40 ml. of toluene. Afterstripping the solvent, 2,6-diisopropylpyrazabole was obtained as an oil.

PartB All of the product from Part A was dissolved in 200 ml. of carbontetrachloride and exhaustively chlorinated by bubbling in chlorine untilthe yellow color persisted. The crude product was purified bysublimation at 200 C./ 1 mm. There were obtained 5.3 g. (60 percentoverall yield) of 4,4,8,8-tetrachloro-2,6- diisopropylpyrazabole in theform of a colorless solid which was purified further byrecrystallization from heptane; m.p., 207208 C. Anal. Calcd. for

C H B Cl N.,: C, 37.7; H, 4.72; C1, 37.1

Found: C, 38.7; H, 5.10; Cl, 36.8.

EXAMPLE 24 4,8-Dichloro-2,6-bis(perfluoroisopropyl)pyrazabole Part APyrazole (68 g.) and hexafluoroacetone (180 g.) were heated in anautoclave for two hours at 200 C. The unreacted hexafluoroacetone wasvented and 125 g. of sulfur tetrafluoride and 30 g. of hydrogen fluoridewere added. The mixture was heated at 125 C. for 2 hours. It was thencooled and poured into 4 liters of water. After two hours the solid wasfiltered and taken up in 300 ml. of hot benzene; the solution wasfiltered and evaporated in a stream of N The product was sublimed at 100C/8 mm. to obtain 4-perfluoroisopropylpyrazole in percent yield. Anal.Calcd. for

C H F N C, 30.5; H, 1.27; F, 56.4; N, 11.9

Found: C, 30.6; H, 1.38; F, 56.7; N, 11.1

Part B 4-Perfluoroisopropylpyrazole (47.2 g., 0.2 mole) and 15 g. (0.22mole) of trimethylamine borane were refluxed overnight in 250 ml. ofxylene. The solvent was removed at reduced pressure and the residue wasdistilled to yield a total of 32.4 g. (65.5 percent) of liquid2,6-bis-(perfluoroiso-propyl)pyrazabole, the main fraction of whichboiled at 70-78 C./2 mm. and solidified on cooling; m.p., 4950 C. TheNMR spectrumhasasinglet at 1.917. Anal. Calcd. for

Found: C, 29.6; H, 1.88; F, 55.2

Part C A 3.2 g. sample of crude 2,6-bis-(perfluoroisopropyl)-pyrazabolewas dissolved in a 1: 1 mixture of chloroform and carbon tetrachlorideand chlorine was bubbled in until the yellow color pering compoundsfurther may be represented by the general formula preferably or N,appropriately substituted or satu-' rated where necessary to satisfy itsvalence bonds, and Q is a polyradical, being either a pair of diradicallinking units or a tetraradical linking unit. These are illustrated byExamples 14-18 and constitute the most general utility of compounds offormula I. These polymers are comprised substantially of a plurality ofunits having the structure with R R Q and Z as defined above. Thecompounds of the instant invention, also, are useful for initiating thepolymerization of olefins and, moreover, are able to be copolymerizedtherewith, as shown by Example 12. Finally, as exemplified by Example 13wherein a carbonyl group is reduced to a hydroxymethylene group, thepyrazaboles and sym-triazaboles of this invention may be used asreducing agents.

During the course of the experimentation relating tothe presentinvention, it was discovered that still another type of polymericpyrazabole may be prepared. Instead of performing the pyrazabole andsubsequently converting to polymer by reaction thereof with an activehydrogen-containing material, the polymeric pyrazabole may be formeddirectly from a dipyrazole, and preferably one free of active hydrogenexcept for ring NH, and a boron-containing compound of the typepreviously described for the formation of the tetraazadiborines. Therequisite dipyrazole may be represented by the formula wherein the Rgroups, Q" and n are as defined above. They are tough, high meltingmaterials and may be converted into various shaped structures byextrusion, injection or compression molding, casting techniques, and thelike. In the process of forming the polymeric pyrazaboles directly, useof an active hydrogen-free dipyrazole is preferred since the use of suchmaterials precludes the formation of three-dimensional polymericnetworks via the competing (cross-linking) reaction which has beenpreviously described as occurring between a preformed pyrazabole and anactive hydrogen-containing material. As exemplification of the processof direct formation of polymeric pyrazaboles are presented the followingexamples.

EXAMPLE 25 Polymer from 3,5,3',5'-Tetrarnethyl-4,4-xylylenedipyrazoleand Triethylborane PartA A solution of g. of l,4-bis(2,2-

diacetylethyl)benzene in 800 ml. of ethanol at 60 C. was added to asolution of 32 g. of hydrazine hydrate in 400 ml. of methanol. Anexothermic reaction took place and a solid separated. The mixture wasboiled for 1 hour and then filtered to obtain 67 g. of 3,5,3',5'-tetramethyl-4,4-xylylenedipyrazole in the form of a white solid meltingat 334335 C. The compound was converted to the diacetyl derivative byrefluxing with a large excess of acetic anhydride for one-half hour andstripping the solution to dryness. The product was recrystallized fromtoluene, hexane to yield a crystalline solid melting at l53-l54 C. TheNMR spectrum was in agreement with the proposed structure: singlets at2.96, 6.30, 7.33, 7.48, and 7.9011- with relative areas of2:2:3:3:3.Anal. Calcd. for

I Found: C, 69.7; H, 7.07

Part B To a nitrogen-blanketed suspension of 14.7 g. (0.05 mole) of3,5,3',5'-tetramethyl-4,4-xylylenedipyrazole in 300 ml. of toluene wereadded 13.7 ml. (0.1 mole) of triethylborane. The mixture warmedspontaneously to 32 C. and most of the solid dissolved. The mixture washeated at reflux overnight and the theoretical amount of ethane wasevolved, as measured by a gas meter. The mixture was cooled to roomtemperature and filtered to obtain a polymer having a plurality of unitshaving the structure Et Et \B/ OH on I 3 N/ \N a cHrom 0 I I Q bra CH;

The polymer softens above 360C. on a melting point block. When pressedbetween platens at 220 (3., the polymer is converted into a tough,transparent, hardsurfaced film which is useful for packaging.

EXAMPLE 26 Polymer from 4,4-Methylenedipyrazole and Triethylborane Amixture of methylene bromide (174 g., 1 mole) and pyrazole (136 g, 2moles) was heated in an autoclave at 200 C. for 3 hours. The reactionproduct was a spongy, rock-like solid. It was dissolved in 900 ml. ofboiling water and the solution made slightly basic with 50 percentsodium hydroxide. A brown solid precipitated. It was purified byrecrystallization from boiling water and finally by sublimation.

From five such runs were obtained a total of 116 g. (3 1 .4 percent) ofwhite solid 4,4- methylenedipyrazole; m.p. 194-l96 C. It is watersoluble, giving an immediate precipitate with Ag ion. The NMR spectrumhas two singlets of equal intensity at 2.28 and 6. 171-.

Anal. Calcd. for

Found: C, 56.0; H, 5.55; N, 38.6

Triethylborane (13.7 ml.) was added under nitrogen to a suspension of7.4 g. of 4,4-methylenedipyrazole in 300 ml. of toluene. The soliddissolved immediately. The solution was stirred and heated at refluxuntil 2.5 liters of ethane were evolved. The solution was cooled and asolid precipitated. It was recovered by filtration, washed with ether,and air-dried to obtain 13.4 g. of polymer of the structure indicatedbelow.

The polymer is soluble in hot toluene and softens above 300 C. on amelting point block. When pressed between platens at 230 C./ 10,000psi., it yields translucent films which are useful for packaging. Theinfrared absorption spectrum of one of these films exhibits bands at2,920, 2,850, 1,442, 1,410, 1,342, 1,264, 1,118, 1,098, 1,050, 1,019,902, 856, 848, and 827 cm. 1

EXAMPLE 27 Polymer from 4,4'-Methylenedipyrazole and TrimethylamineBorane On a melting point block, the polymer softened at 250-270 C. andslowly turned amber at 380-430 C. The inherent viscosity (0.1 percent indimethylformamide at 25C.) is 0.09. A solution of the polymer inhexamethylenephosphorarnide was cast and dried to yield a transparentfilm. Anal. Calcd. for

Found C, 48.6; H, 5.93; N, 32.8

EXAMPLE 28 Polymer from 3 ,5,3 ,5 '-Tetraphenyll,6-hexamethylenedipyrazole and Triethylborane Example 25 is repeatedessentially as described except that the bis(diketone) is replaced withl,1,8,8- tetrabenzoyloctane. The polymeric repeat unit now has thestructure Et /Et EXAMPLE 29 (III) wherein R and R are as subsequentlydefined, and R and R may be selected from a group which consists ofhydrogen, halogen, l-pyrazolyl, alkyl, aryl, alkoxy, haloalkoxy,aryloxy, alkylamino, arylamino, azido, alkylmercapto and arylmercapto; Rand R attached to the same boron conjointly are wherein Z is a saturatedheteroatom which may be selected from a group which consists of oxygen,sulfur, nitrogen and phosphorus, and Q is a hydrocarbon, preferably of4-30 carbon atoms, polyradical which may be selected from a group whichconsists of a pair of diradical linking units and a tetraradical linkingunit,

with the proviso that when li and R are taken conjointly, the resultantstructure is a polymeric repeat wherein Z and Q are as previouslydefined, X may be selected from a group which consists of N and CR, andR R and R may be selected from a group which consists of hydrogen,alkyl,halogen, haloalkyl, aryl, cyano, alkoxy, alkoxy-carbonyl,arylamino, nitro, acyl, mercapto and hydroxy, and R and R conjointly maybe selected from a group which consists of benzo and naphtho; X may beselected from a group which consists of X, as previously defined, andC(Q"),, wherein Q" isa ,w-hydrocarbylene of one to 18 carbon atoms,preferably alkylene of one to carbon atoms, p-phenylene,p,p'-diphenylene and p-xylylene, and n is zero or one, with the provisothat when X is C(Q),,, the resultant structure is a polymeric repeatunit It in wherein R, R, R and R are as previously defined.

EXAMPLE 30 4,4-Difluoropyrazabole To a solution of 25.4 ml. (0.2 mole)of BF etherate in 100 ml. of ether there was added slowly a solution of18.6 g. (0.1 mole) of potassium dihydrobis( 1- pyrazolyl)borate in 100ml. of tetrahydrofuran. An exothermic reaction took place, and a solidbegan to precipitate. When the exothermicity subsided, the reactionmixture was stripped.

Another run on the same scale involved reverse addition. The two runswere inadvertently combined and were hence processed together bydissolving the stripping residue in water and extracting with methylenechloride. The extracts were stripped yielding 29 g. (75 percent) of anoil which solidified on standing. This oil was further purified bydistillation in vacuo. The product boiled at 100/4.7 mm. and melted,after recrystallization from hexane, at 8788 C.

Anal. Calcd. for

C l-1.8 1 1%: C, 36.7; H, 4.08; N, 28.6

Found: C, 36.9; H, 4.68; N, 28.4

The nmr spectrum had a doublet (J 2.3) at 2.091, an unresolved doubletat 2.357 and poorly resolved triplet (J ==2) at 3.61 in 1:1:1 ratio. TheEH hydrogens were detectable by integration in the 4-91' range. Theinfrared spectrum contained a strong EH multiplet similar to that ofpyrazabole.

The B nmr spectrum had two triplets at +l7.7 ppm (J 21) and +26.5 ppm (J110) from trimethyl borate.

EXAMPLE 31 4,4-Diethylpyrazabole To a solution of 30 ml. (0.4 mole) oftrifluoroacetic acid, stirred under nitrogen in 200 ml. of benzene,there was added 56.4 ml. (0.4 mole) of triethylborane. Evolution ofethane commenced spontaneously and proceeded rapidly, necessitatingoccasional cooling. When 9.6 l. of ethane had been evolved, a solutionof g. (0.4 mole) of potassium dihydrobis(1-pyrazolyl)- borate in 400 ml.tetrahydrofuran was added slowly. An exothermic reaction took place.When this reaction subsided, the tetrahydrofuran was distilled out; theresidue was stirred with water and extracted with ether. Stripping ofthe organic layer gave an oil which was distilled, collection being madeof the 1 l0l40 C./ 2.7 mm cut. This product solidified on standing andwas obtained in 62 g. (72 percent) yield. The material was purifiedfurther by recrystallization from petroleum ether; m.p. 61-62 C. Anal.Calcd. for

C H B N C, 55.5; H, 8.33; N, 25.9

Found: C, 55.5; H, 8.15; N, 26.2

The nmr spectrum consisted of a doublet (J 2.5) at 2.431', a triplet (J2.5 at 3.691- and a three-peak multiplet centered at 9.341, in 4:2:10ratio. The BB hydrogens can be seen by integration in the 30107 range.

The B nmr spectrum had a broad peak at +l6.5 ppm overlapping anunresolved triplet at +266 ppm, from trimethyl borate.

EXAMPLE 32 4,4-Diethylpyrazabole A suspension of 38 g. (0.2 mole) ofp-toluenesulfonic acid monohydrate was stirred and refluxed in 250 ml.of toluene until no more water was evolved into the attached Dean-Starktrap and a clear solution resulted. To this solution there was addedunder nitrogen 28.2 ml. (0.2 mole) of triethylborane. The resultingsolution was stirred and refluxed until 5.41. of gas was evolved. Theresulting solution was cooled, transferred rapidly to an addition funneland added dropwise to a solution of 40 g. (0.2 mole) of KH B(pz) in 400ml. of dry tetrahydrofuran. The mixture was refluxed briefly and wasthen poured into 1 l. of water. The layers were separated, and theaqueous layer was extracted twice with hexane. The extracts werecombined with the original organic layer, filtered and stripped. Theresidual oil was distilled in vacuo yielding 25 g. (58 percent) of themain cut, b.p. l05-112 C./3.7 mm. The infrared spectrum was identical tothat of authentic 4,4 -diethylpyrazabole from Example 31.

EXAMPLE 33 L 4,4-Dibutylpyra2abole A suspension of 38 g. (0.2 mole) ofp-toluenesulfonic acid monohydrate was refluxed in 250 ml. toluene, thewater being removed via a Dean-Stark trap. When the theoretical amountof water had been collected, the clear solution was cooled and 0.2 moleof tributylborane was added. The solution was stirred and refluxed until0.1 mole of butane was evolved. The clear solution was cooled andtransferred rapidly to an addition funnel. It was added dropwise to asolution of 40 g. (0.2mole) of KH B(pz) in 400 ml. of

tetrahydrofuran. The mixture was refluxed briefly and was then pouredinto 1 l. of water. The layers were separated, and the aqueous layer wasextracted twice with hexane. The organic extracts were combined, driedover MgSO.,, filtered and stripped. The residue was purified bydistillation, the main cut boiling at 142144 C./1.7 mm, n,, 1.502. Theproduct was obtained in 33.4 g. (62 percent) yield.

Anal. Calcd. for

C H B M: C, 61.7; H, 9.57; N, 20.6

Found: C, 61.7; H, 9.86; N, 20.6.

The nmr spectrum had two overlapping doublets (unresolvable) centered at2.521, a triplet (J 2.4) at 3.837 and a complex multiplet with sharppeaks at 9.17 and 9.251 in 2: 1:9 ratio.

EXAMPLE 34 Utility Of Unsymmetrical Pyrazaboles as Reducing Agents To achloroform solution of ar-allylpalladium chloride dimer there was addedat room temperature a chloroform solution of 4,4-diethylpyrazabole.Within a few seconds precipitation of metallic palladium commenced. Themetal was deposited in part as a shiny mirror on the walls of the testtube.

In a similar experiment 4,4-dibutylpyrazabole was used. Here, too,precipitation of palladium metal was rapid and complete.

EXAMPLE 35 4,4-Dichloro-8,S-diethylpyrazabole Chlorine was bubbled intoa solution of 43.2 g. (0.2 mole) of 4,4-diethylpyrazabole in 500 ml. ofcarbon tetrachloride until the yellow color persisted. The solution wasstripped to dryness, and the residue was recrystallized from hexane. Theproduct was obtained in 51.5 g. (90.5 percent) yield as colorlesscrystals, m.p. 9091 C. Anal. Calcd. for

c,.,H,,B,c1,N,: C, 42.1; H, 5.62; Cl, 24.9; N, 19.7

Found: C, 41.5; H, 5.30; Cl, 24.4; N, 19.7

The nmr spectrum had doublets at 1.761- (J 2.5) and 2.251- (.1 2.3), atriplet at 3.371- (J 2.4) and a multiplet at about 9.41- in 1: 1: 1:5ratio.

EXAMPLE 36 4,4-Diethyl-8,8-o-phenylenedioxypyrazabole A mixture of 10.8g. (0.05 mole) of 4,4-diethylpyrazabole and 5.5 g. (0.05 mole) ofpyrocatechol was refluxed in 150 ml. xylene. Hydrogen evolution wassluggish. The solvent was distilled out, whereupon the rate of hydrogenevolution increased, 2.41. of H finally being collected. The crudereaction mixture was chromatographed on alumina. Elution with hexanegave 1.7 g. of a solid which was identified as 4,4-diethylpyrazabole. Byswitching to ether-hexane as the eluent, a second product fraction wasobtained in 11.8 g. yield (79 percent yield based on unrecovered4,4-diethylpyrazabole). This material was recrystallized from hep tane;m.p. 82--8 3 C. Anal. Calcd. for

C, H B N,O C, 59.6; H, 6.22; N, 17.4

Found: C, 59.2; H, 5.97; N, 17.6

The nmr spectrum had two overlapping doublets at 2.231- (J 2.6) and2.30r (J 2.5), each split further ii. by 0.6 cps, a singlet at 3.127, atriplet at 3.561- (J 2.55) and a triplet at 9.291- in 1:1:2: 1:5 ratio.

EXAMPLE 37 Polymer from 4,4-Dibuty1pyrazabole Hydroquinone A mixture of5.4 g. (0.02 mole) of 4,4dibuty1- pyrazabole and 2.2 g. (0.02 mole) of1,4-hydroquinone was stirred and refluxed in 50 ml. of odichlorobenzene.Hydrogen was evolved. The evolution ceased after about 0.6 l. of H hadbeen collected. A white solid separated which was filtered and obtainedin 5.0 g. yield; m.p. l45-l50 C. It could be pressed to a tough film ofthe type useful for packaging.

The infrared spectrum of the product lacked the BH bands but had an OHband at 3,350cmf, indicating endcapping of the polymer by OC l-l Ol-lgroups.

EXAMPLE 38 4,4-Diethyl-8,8-bis( l-pyrazolyl)pyrazabole To a mechanicallystirred slurry of 16 g. (0.05 mole) of potassium tetrakis(l-pyrazolyDborate in 200 ml. toluene there was added 42 ml. of a 1.7Msolution of diethylboryl methanesulfonate in toluene. The slurry wasstirred and refluxed for 1 hour. It was then cooled, stirred with waterand extracted with ether. The or ganic layer was dried, filtered andstripped, and the residue was chromatographed on acid-washed alumina,eluting first with hexane (which removed some 4,4,8,8-tetraethylpyrazabole), then with ether which eluted the desired product.product was obtained in 12.7 g. (73 percent) yield and was furtherpurified by recrystallization from heptane; m.p. 120-l 21 C. Anal.Calcd. for

C H B N C, 55.8; H, 6.32; N, 32.2

Found: C, 55.3; H, 6.45; N, 32.8

The nmr spectrum was confirmatory for 4,4-diethy1- 8,8-bis(l-pyrazolyDpyrazabole. The spectrum had two overlapping doublets at2.261", a doublet (J 2.6, J 0.7) at 2.547, a doublet (J 2.3, J 0.6) at3.051, a triplet (J 2.5) at 3.487, a triplet (overlapping doublets J =23and 1.7) at 3.741 and an asymmetric doublet (B-ethyls) at 9.487 in thecorrect 4:2:22212: 10 ratio.

and 1,4-

EXAMPLE 39 4,4-Diethyll ,3 ,5,7-tetramethylpyrazabole To a mechanicallystirred slurry of 29 g. (0.12 mole) of potassiumdihydrobis(3,5-dimethyl-lpyrazoly1)borate in 400 ml. of toluene therewas added slowly ml. of a 1.2M solution of diethylboryl methanesulfonatein toluene. A moderately exothermic reaction took place, and the flaskcontents gelled par-- tially as potassium methanesulfonate precipitated.The slurry was refluxed with stirring for 1 hour and was then cooled andstirred with 500 ml. of water. The organic layer was separated, dried,filtered, and stripped. The residue solidified on cooling. There wasobtained 26 g. (96 percent yield) of a solid which was purified byrecrystallization from methanol; m.p. 9l-92 C. This material could alsobe distilled in vacuo, b.p. 158 C/ l .5 mm. Anal. Calcd. for

H, 9.56; N, 20.6 Found: C, 62.5; H, 9.2 0.

The infrared spectrum contained the BH band as a complex multiplet inthe 2,2702,450 cm range.

The nmr spectrum was confirmatory for4,4-diethyll,3,5,7-tetramethylpyrazabole. The spectrum had singlets at4.14, 7.66, and 7.781- as well as a complex multiplet (B-ethyls) in thecorrect 1:3:3:5 ratio.

All of the 4,4-disubstituted pyrazaboles of this invention absorbstrongly in the ultraviolet region. The opacity toward certainwavelengths of ultraviolet light (i.e., light having a wavelength lessthan 400 millimicrons) which these compounds exhibit makes them usefulin the protection of light-sensitive or light-fugitive materials againstdegradation by ultraviolet light. The 4,4-disubstituted pyrazaboles canbe incorporated in films and fibers of natural or synthetic organicpolymers, many of which fail prematurely when exposed intermittently orcontinuously to ultraviolet light. Acting as absorbers, the pyrazaboleswill serve to reduce deterioration of the polymers and/or of the dyesused therewith caused by ultraviolet radiation. The 4,4- disubstitutedpyrazaboles of this invention are also valuable for incorporation incontainers, covers for display cases and the like where protection ofthe contents from the deleterious action of ultraviolet light isdesired.

UV spectral data on the asymmetric pyrazaboles of this invention are setforth in TABLE VI.

All of the products of this invention, the pyrazaboles, sym-triazabolesand polymers prepared from them, are useful as combustible additives tocompositions employed in fireworks displays to impart pleasing greencolors to the flames.

Since obvious modifications and equivalents will be evident to thoseskilled in the chemical arts, I propose to be bound solely by theappended claims.

I claim:

1. A compound having the formula:

wherein R, R, R and R are hydrogen, fluorine, chlorine, bromine, iodine,alkyl of up to 18 carbon atoms, phenyl, substituted phenyl in which thesubstituents can be lower alkyl of up to six carbon atoms and/or halo,lower alkoxy of up to six carbon atoms, phenoxy, haloloweralkoxy of upto six carbon atoms, lower alkylamino of up to six carbon atoms,anilino, azido, l-pyrazolyl, lower alkyl mercapto of up to six carbonatoms and phenylmercapto, R, R, R and R being chosen such that when atleast one of R and R is difierent from R and R, neither R nor R can bel-pyrazolyl;

R, R and R are hydrogen, chlorine, bromine and iodine, alkyl of up to 18carbon atoms, haloloweralkyl of up to six carbon atoms, phenyl,substituted phenyl in which the substituents can be lower alkyl of up tosix carbon atoms and/or halo, lower alkoxy carbonyl in which the alkylgroup contains up to six carbon atoms, cyano, lower alkoxy of up to sixcarbon atoms, anilino, nitro, carboxylic acyl of up to eight carbonatoms, mercapto and hydroxy, and R and R when taken conjointly are benzoor naphtho.

2. The compound of claim 1 wherein R, R and R are hydrogen; and R, R, Rand R are l-pyrazolyl, 4,4,8,8-tetrakis( l-pyrazolyl)pyrazabole.

3. A compound of claim 1 wherein R, R and R are hydrogen; and R, R, Rand R are halogen, 4,4,8,8- tetrahalopyrazabole.

4. A compound of claim 1 wherein R, R and R are hydrogen; and R, R, Rand R are lower alkyl of one to six carbon atoms,4,4,8,8-tetraloweralkylpyrazabole.

5. The compound of claim 1 wherein R, R and R are hydrogen; R and R arephenyl; and R and R are l-pyrazolyl, 4,8-diphenyl-4,8-bis(lpyrazolyl)pyrazabole.

6. The compound of claim 1 wherein and R, R, R,

7. A compound of claim 1 wherein R, R, R, R and R are hydrogen; and Rand R are lower alkyl of l to 6 carbon atoms,1,3,5,7-tetraloweralkylpyrazabole.

8. The compound of claim 1 wherein R, R, R, R and R are hydrogen and Rand R are phenyl, 1,3,5 ,7- tetraphenylpyrazabole.

9. A compound of claim 1 wherein R, R, R, R and R are hydrogen; and R ishalogen, 2,6- dihalopyrazabole.

10. The compound of claim 1 wherein R= R R R R H and R R fluorine, 4,4difluoropyrazabole.

11. The compound of claim 1 wherein R= R R R R H and R R ethyl,4,4-diethylpyrazabole.

12. The compound of claim 1 wherein R= R R R R H and R R butyl,4,4,-dibutylpyrazabole.

13. The compound'of claim 1 wherein R R ethyl, R R R H and R R chlorine,4,4- dichloro-8,8-diethylpyrazabole.

14. The compound of claim 1 wherein R and R taken together represento-phenylenedioxy, R R

H and R R ethyl, 4,4-diethyl-8,8-o-phenylenedioxypyrazabole.

15. The compound of claim 1 wherein R R 1- pyrazolyl, R R R H and R Rethyl, 4,4- diethyl-8,8-bis( l-pyrazolyl)pyrazabole.

' 27 28 16. The compound of claim 1 wherein R R R 18.2,6-Bis(perfluorolow eralkyl)pyrazabole wherein H, R R methyl and R Rethyl, 4,4-diethyllower alkyl contains one to six carbon atoms.l,3,5,7-tetramethylpyrazabole. 19.4,4,8,8-Tetrakis(chloroloweralkoxy)pyrazabole 17. l,3,5,7-Tetrakis(perfluoroloweralkyhpyrazabole wherein lower alkyl contains one to sixcarbon atoms. wherein lower alkyl contains 1-6 carbon atoms. 5

I CERTEFECATE OF CGRRECTKGN iatent No. 3,681, 381 Dated August '1, 1972I Inventor(5) Swiatoslaw Trofimenko It is certified that error appearsin the above-identified patent and that said Letters Patent are herebycorrected as shown below:

On the front page format, "Attorney James W. Ryan" should read AttorneyJames 1 1.; Ryan in the Abstract, after the formula insole" whereincolumn all the matter beginning with line 22 to the and of the columnshould be canceled and inserted after line 29', column'j; column 1?,line 36, "performing" should read ,pmiormzl.n v column 20, line 8, abracket should be inserted after "M '5 column 25, Table VI, Example 3?,"55.93 chould read a 5.9--=; column 26, line 48, after "wherein" insertR, Cancel columns 15 and 16 and substitute the attached sheet:

Signed and sealed this 26th day of'Decemb er 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR.

ROBERT GOTTSCHALK Attestlng Officer Commissioner of Patents USCOMM- DC60376-P69 u.s GOVERNMENT PRINTING OFFICE: 1969 0-366-334.

1. SYMMETRICAL PYRAZABOLES AND SYM-TRIAZABOLES OF THE FORMULA 2.UNSYMMETRICAL PYRAZABOLES AND SYM-TRIAZABOLES AS RESPRESENTED BY FORMULA(1), WHEREIN R AND R1 MAY BE HYDROGEN, HALOGEN, 1-PYRAZOLYL, ALKYL,ARYL, ALKOY, HALOALKOXY, ARYLOXY, ALKYLAMINO, ARYLAMINO, AZIDO,ALKYLMERCAPTO AND ARYLMERCAPTO; X MAY BE N OR CR4; R2, R3 AND R4 MAY BEHYDROGEN, ALKYL, HALOGEN, HALO-ALKYL, ARYL, CYANO, ALKOXY, ARYLAMINO,ALKOXYCARBONYL, NITRO, ACYL, MERCAPTO AND HYDROXY WITH THE PROVISO THATR2 AND R4 TAKEN TOGETHER MAY REPRESENT A FUSED BENZO OR NAPHTHOSTRUCTURE; AND R5 AND R6 ARE DEFINED THE SAME R AND R1 WITH THE PROVISOTHAT 1-PYRAZOLYL IS EXCLUDED AS A SUBSTITUENT IN THE CASE OF R5 AND R6.IN THE UNSYMMETRICAL PYRAZABOLES AND SYMTRIAZABOLES OF THIS INVENTION,AT LEAST ONE OF R AND R1 IS CHEMICALLY DISTINGUISHABLE FROM R5 AND R6.2. The compound of claim 1 wherein R2, R3 and R4 are hydrogen; and R,R1, R5 and R6 are 1-pyrazolyl, 4,4,8,8-tetrakis(1-pyrazolyl)pyrazabole.3. A compound of claim 1 wherein R2, R3 and R4 are hydrogen; and R, R1,R5 and R6 are halogen, 4,4,8,8-tetrahalopyrazabole.
 3. THE PROCESSES BYWHICH THE PYRAZABOLES AND SYMTRIAZOBLES OF THIS INVENTION MAY BEPREPARED.
 4. POLYMERS HAVING INCORPORATED THEREIN THE PYRAZABOLE ANDSYM-TRIAZABOLE STRUCTURE. THE COMPOUNDS OF THE INVENTION ARE USEFUL ASPOLYMERIZATION INITIATORS, REDUCING AGENTS AND AS REACTANTS IN THEFORMATION OF CONDENSATION POLYMERS CONTAINING THE PYRAZABOLE ANDSYM-TRIAZABOLE MOIETIES.
 4. A compound of claim 1 wherein R2, R3 and R4are hydrogen; and R, R1, R5 and R6 are lower alkyl of one to six carbonatoms, 4,4, 8,8-tetraloweralkylpyrazabole.
 5. The compound of claim 1wherein R2, R3 and R4 are hydrogen; R and R5 are phenyl; and R1 and R6are 1-pyrazolyl, 4,8-Diphenyl-4, 8-bis(1-pyrazolyl)pyrazabole.
 6. Thecompound of claim 1 wherein and R, R1, R2, R3, R4, R5 and R6 arehydrogen, pyrazabole.
 7. A compound of claim 1 wherein R, R1, R4, R5 andR6 are hydrogen; and R2 and R3 are lower alkyl of 1 to 6 carbon atoms,1,3,5,7-tetraloweralkylpyrazabole.
 8. The compound of claim 1 wherein R,R1, R4, R5 and R6 are hydrogen and R2 and R3 are phenyl,1,3,5,7-tetraphenylpyrazabole.
 9. A compound of claim 1 wherein R1, R2,R3, R5 and R6 are hydrogen; and R4 is halogen, 2,6-dihalopyrazabole. 10.The compound of claim 1 wherein R R1 R2 R3 R4 H and R5 R6 fluorine,4,4-difluoropyrazabole.
 11. The compound of claim 1 wherein R R1 R2 R3R4 H and R5 R6 ethyl, 4,4-diethylpyrazabole.
 12. The compound of claim 1wherein R R1 R2 R3 R4 H and R5 R6 butyl, 4,4,-dibutylpyrazabole.
 13. Thecompound of claim 1 wherein R R1 ethyl, R2 R3 R4 H and R5 R6 chlorine,4,4-dichloro-8,8-diethylpyrazabole.
 14. The compound of claim 1 whereinR and R1 taken together represent o-phenylenedioxy, R2 R3 R4 H and R5 R6ethyl, 4,4-diethyl-8,8-o-phenylenedioxypyrazabole.
 15. The compound ofclaim 1 wherein R R1 1-pyrazolyl, R2 R3 R4 H and R5 R6 ethyl,4,4-diethyl-8,8-bis(1-pyrazolyl)pyrazabole.
 16. The compound of claim 1wherein R R1 R4 H, R2 R3 methyl and R5 R6 ethyl,4,4-diethyl-1,3,5,7-tetramethylpyrazabole. 17.1,3,5,7-Tetrakis(perfluoroloweralkyl)pyrazabole wherein lower alkylcontains 1-6 carbon atoms.
 18. 2,6-Bis(perfluoroloweralkyl)pyrazabolewherein lower alkyl contains one to six carbon atoms. 19.4,4,8,8-Tetrakis(chloroloweralkoxy)pyrazabole wherein lower alkylcontains one to six carbon atoms.